While on the search for my wedding dress, I was introduced to a shop called "The Brides' Project". This is a shop that carries pre-loved dresses or donated dresses, where all the profits go to charity.
Though I didn't find my dress there, I tried on quite a few of them and all the dresses were in top quality condition, and the staff very helpful. I tried on many big name dresses, some of which I had seen in magazines later on.
If you are a Toronto (or surrounding area) bride on a budget, I HIGHLY recommend checking it out. They have lots of dresses in every size, and you might luck out and find your perfect dress for half the price.
They also have shoes, veils, garters...etc all of which are so much more reasonably priced then a bridal shop. I bought a nice hair accessory there for $10, where the same thing would have cost $100 in a "real" shop.
Google the name and you should come across the website. I also think there is one in the states.